Electric switches

ABSTRACT

A crossbar switch having a three-dimensional matrix of crosspoint contacts provided by rows, columns and tiers of conductor wires. The tiers of contacts at each cross-point provide a contact set of, say, 12 contact pairs which are housed in an individual housing member. Mounted within each housing member is a comb having a tooth for each contact pair, the tooth engaging one wire, the row wire, of the contact pair. The tip of each tooth engages its respective row wire both in closing and opening the contact set and in fact provides a support for the row wire. The comb is biased into the contact open condition in which the row wires are unstressed.

United States Patent [72] Inventor Gerald David Breeze Coventry, England [21] Appl. No. 33,616 [22] Filed May 1, 1970 [45] Patented Dec. 28, 1971 [73] Assignee The General Electric Company Limited London, England [32] Priority May 1, 1969 [33] Great Britain 1 22,287/69 [541 ELECTRIC SWITCHES 6 Claims, 5 Drawing Figs.

[52] 11.5. Cl 200/175, 200/177, 338/109, 338/112 [51] Int. Cl ..H01h 63/00 [50] Field of Search. 200/175, 176,177,178;335/l08,109,110,112,113,114, 115,116,117,118

[56] References Cited UNITED STATES PATENTS 2,339,472 l/1944 Frederick 335/112 Primary ExaminerR. F. Staubly Assistant Examiner-Gale R. Peterson Attorney-Kirschstein, Kirschstein, Ottinger & Frank ABSTRACT: A crossbar switch having a three-dimensional matrix of cross-point contacts provided by rows, columns and tiers of conductor wires. The tiers of contacts at each crosspoint provide a contact set of, say, 12 contact pairs which are housed in an individual housing member. Mounted within each housing member is a comb having a tooth for each contact pair, the tooth engaging one wire, the row wire, of the contact pair. The tip of each tooth engages its respective row wire both in closing and opening the contact set and in fact provides a support for the row wire. The comb is biased into the contact open condition in which the row wires are unstressed.

ELECTRIC SWITCHES This invention relates to electric switches and particularly to crossbar switches such as may be used in telephone exchanges.

Two examples of crossbar switch are described in the complete specification of British Pat. application No. 57555/66 and the present invention is directed to an improvement in such switches.

A feature of the switch of the present invention in common with that of the above I patent application, is a conductor matrix comprising a plurality of tiers of conductors which, in each tier are arranged as rows and columns so that corresponding row wires in the different tiers form row planes and corresponding column wires in the different tiers form column planes, the intersection of a row plane and a column plane providing a crosspoint contact set which thus comprises a contact pair in each tier.

Each crosspoint contact set is then operable by a respective contact operating member which deflects all the row wires at the crosspoint into electrical contact with the column wires at the cross-point.

According to one feature of the invention each crosspoint contact set has a respective housing member which locates the column wires of that cross-point, the housing members of each column interlocking to prevent movement transverse to the column.

According to a second feature of the invention manufacture of the conductor matrix comprises assembly of individual contact operating members in their respective housing members, assembly of a matrix of the housing members and, the endwise insertion of the row wires and column wires to form the conductor cross-points.

According to a further feature of the invention the contact operating member is a comb member having a cantilever tooth for each contact pair, the tip of the tooth being formed so as to displace the row wire into and out of contact with the column wire.

According to a yet further feature of the invention the column wires extend into further rows of the conductor matrix in which rows the contact sets have contact pairs in selected groups only, of the tiers, the grouping varying with the row so that a multiwire path through the switch can be established with a choice of row plane, column plane and tier group, by operation of two contact sets in a column.

A crossbar switch in accordance with he invention will now be described, by way of example, with reference to the accom panying drawings, of which: FIG. 1 is an exploded front elevation of the crossbar switch showing, in the upper part a conductor matrix, and in the lower part the operating mechanism; FIG. 2 is a diagrammatic view of the conductor matrix; FIG. 3 is part of a left-hand end elevation of the conductor matrix; FIG. 4 is an underneath plan view of one column of the conductor matrix and FIG. 5 is a sectional elevation on the line V-V of FIG. 3.

The conductor matrix comprises 12 tiers of conductor wires, shown in FIG. 2, which, in each tier, are arranged as rows and columns. It will be appreciated that this designation of rows and columns is for convenience only in referring to the conductors of a rectangular coordinate matrix. There are basically l0 row wires and column wires in each tier, with an additional three rows which will be called level-switching rows. The wire arrangement of the level-switching rows is modified from the basic arrangement-as will be explained. The 12 tiers are superimposed so that corresponding columns in the different tiers form column planes and corresponding rows form row planes. The intersection of a row plane and a column plane provides a crosspoint contact set of 12 contact pairs, each such pair being formed by a row wire and a column wire. In each tier the row wires are spaced apart slightly from the column wires so that normally there is no electrical contact between them.

Clearly, any row wire (apart from those in the levelswitching rows) can be connected to any column wire by deflecting one or the other at the appropriate cross-point. However, the present switch is required to make multiple connections in unison for telephone purposes, and for this reason all 12 contact pairs of a crosspoint contact set are operated in unison. In general only four of the 12 connections are sufficient for a particular telephone call and its supervision, and the purpose of the three level-switching rows mentioned above is to select one of the three groups, each group comprising four contact pairs, that are provided by the 12 tiers, when all 12 contact pairs are operated.

Each contact set has a respective comb member having 12 cantilever teeth which interleave the tiers so that the tip of one tooth is adjacent to each contact pair. A contact set is then operated by driving the comb transverse to the tiers so that each tooth tip drives a row wire into contact with a column wire.

Operation of the combs in this matrix may be effected by either of the mechanisms described in the above specification, that is, a mechanical or electrical latching mechanism for selecting and maintaining operated a particular contact set, or, preferably, by means of the mechanism described in copending British Pat. application Nos. 40949/69 and 40950/69, and appearing in the lower part of FIG. 1.

The latter mechanism is, briefly, as follows. Each column of the matrix has associated with it a respective electromagnet assembly 62, sometimes referred to as a bridge magnet. Each such bridge magnet has an armature 78 which extends the length of the column and which carries a column of interposer arms, one for each of the 13 rows. Operation of the bridge magnet causes the interposer arms to move substantially lengthwise towards the comb members. The interposer arms are flexible in the row planes and each carries an interposer block at its extremity. The interposer blocks are normally displaced slightly in the row directionfrom the bottom ends 32 of the comb members so'that operation of the bridge magnet alone causes no movement of the combs in the respective column because of the above misalignment of comb and interposer block.

Each row of interposer arms is coupled to a bar which extends the length of the row and is driven longitudinally by an electromagnet sometimes referred to as a select magnet. The select magnets are housed in an assembly 123 at one end of the switch. Operation of a select magnet causes all of the interposer arms of the respective row to move in a direction such as to align the interposer blocks and their respective comb members in the row. Subsequent operation of a bridge magnet then drives the one comb which lies in both the selected row and the selected column. I

Operation of a particular one of the contact sets can thus be effected selectively. It will be noted that, because of the flexible nature of the interposer arms, operation of one contact set in a row does not prevent coincident operation of a further contact set in the same row. When a bridge magnet has been energized to drive a particular interposer block, that block becomes trapped and the select magnet which had made the selection of that block may then be released for subsequent selection of a further contact set in the same row.

External connections to the groups of wires of each row plane provide outlets from the switch while inlets are applied, indirectly, to groups of wires of selected column planes. The particular group of column wires in a column plane is selected by means of the level-switching rows mentioned above. In setting up a four-wire route through the switch, therefore, two select magnets are operated, one to select the outlet row and one, in the three level-switching rows, to select and make connection to the particular group of level of four tiers in that row. A bridge magnet is then operated, thus selecting a particular inlet column to the switch, and the two contact sets selected are operated. A four-wire route is thus set up from a chosen one of 10 four-wire inlets to a chosen one of 30 (10 rows and three levels in each row) four-wire outlets.

A fuller description of the above operating mechanism appears in the patent applications referred to above.

Having described the arrangement and its operation broadly, a detailed description will now be given of the conductor matrix for the switch.

The conductor matrix 51 is shown in the upper part of FIG. 1. Outlet terminal tags 43, of the switch, are connected to row wires 2 extending from left to right within the switch. The matrix is broken away to show a contact set assembly 53 which includes a comb member 25. This comb member is movable vertically in the drawing by engagement of the lower end 32. The lower ends of the comb members of the other nine columns are also shown.

The conductor matrix 51 is mounted on a plate 61 of the mechanism 52 by means of clamping strips 55 having flanges 56. The lower ends 32 of the columns of comb members project through slots in the plate 61 and normally terminate just above respective bridge bars 97 which are movable vertically to drive selected contact sets.

The particular contact set assembly 53 appearing in FIG. 1 is not one of the basic lOXIO matrix of such assemblies but is one in the third row from the rear face of the matrix, that is, in one of the level-switching rows. It can be seen in FIG. 1 that there are, in the exposed contact set assembly 53, only four row conductors andthese occupy the top four tiers. These row conductors (which do not in fact extend beyond the particular contact set assembly) form input connections for the particular column and the particular level-the top one of three. They are connected to terminal pins on the rear face of the matrix.

The arrangement of the conductor matrix can be seen more clearly from the diagrammatic FIG. 2. Discrete contacts have been drawn in this FIG. 2 at each crosspoint of a row conductor 2 and a column conductor 3 for clarity, although in fact there are no such discrete contacts, the wires being quite continuous at the cross-points.

The short row conductors appearing in FIG. 1 are shown in FIG. 2 as the conductors 18. It can be seen how these are arranged in three groups, four in each group, the groups being staggered through the first three rows, the level-switching rows. The three groups are paralleled to provide a net fourwire input to each column. Operation of a level-switching contact set, such as that shown in FIG. 1, will therefore provide four-wire access to a particular column and to a particular one of three levels in that column. One of the four-wire outputs can then be selected by operation of one of the ten standard contact sets in the same column.

Referring now to FIGS. 3, 4 and 5, FIG. 3 shows (part broken away) one column assembly of 13 individual contact set assemblies. These contact set assemblies each comprise 12 contact pairs, and a comb member. Rows 1-3 on the left of FIG. 3 are the level-switching rows previously referred to. The remaining rows contain row wires 2 in every tier. The column wires 3 extend throughout the columns in each of the 12 tiers.

Each housing member 4 is a single molding of plastics material. It comprises a rectangular back plate 6 (to the left of each housing in FIG. 3) of width equal to the pitch of the columns, and of height approximating to that of the 12 tiers. The thickness of the housing 4, equal to the pitch of the rows, is set by upper and lower boss portions 7 and 8, leaving the intermediate space, in front of the back plate 6, to accommodate the contact set. Thirteen of these housing members 4 fit together with the surfaces of the boss portions 7 and 8 of one housing member abutting the back surface 9 of the next, to form the column, as shown in FIG. 3. Spigots 10 extend from the boss portions 7 and 8 and mate with corresponding recesses 11 on the surface 9 of the housing, the housings 4 thus interlocking and forming a unitary column assembly.

The left-hand end of the column assembly, as shown in FIG. 3 is closed by a connector housing 14 and the right-hand end of the column is closed by a side plate not shown. This side plate forms a substitute for a succeeding housing 4 and retains the row wires 2 of row 13 in position.

The back plate 6 of each housing 4 has a portion 15 extending the height of the housing this portion 15 being set forward by a small distance from but still parallel to the remainder of the plate 6. The portion 15 contains l2 pairs of holes 16 corresponding to the l2 tiers of the matrix. The column wires 3 are carried by and are a close fit in these holes 16, the plate 6 thus forming a locatingjig for the column wires. The holes 16 are countersunk on the front face of the portion 15 to facilitate the insertion of the column wires 3. In addition to the holes 16 each housing member 4 has, on the main portion of the back plate 6, asingle vertical row of countersunk holes 17, also corresponding to the 12 tiers of the matrix, but individually positioned slightly below the corresponding holes 16. The holes 17 are used only in the level-switching rows 1-13 for carrying terminal wires 18 in those rows.

The housing 4 is molded so as to provide, in effect, a cutaway portion or channel 21 in each of the upper and lower boss portions 7 and 8. The two channels are vertically aligned and their depth is such that the back plate 6is continuous with them. These channels 21 form a guide for vertical movement of the comb 25.

Movement of the comb within the housing 4 and as guided by the channels 21, is limited in the upward direction by a stop 30 on the comb 25 engaging one end of a recess 31 in the lower boss portion 8. A shoulder 29 on the lower end of the comb 25 engages the channel part of the boss portion 8 to limit downward movement of the comb.

Immediately beneath the upper boss portion 8 a cantilever spring arm 22, molded integrally with the housing 4, projects across and above the back plate 6, inclined slightly downwardly from its root to its free end. This arm 22 is arranged to engage, at its tip, the tip of a corresponding cantilever spring arm 23 integral with the comb 25, as seen in FIG. 5. The double arm arrangement enables the necessary comb deflection to be obtained without excessive stressing of the material.

Referring to the comb 25 more specifically now, this comprises l2 cantilever teeth 26 and the comb back 27. Upper and lower extensions 28 and 32 of the comb back 27 are a close sliding fit in the channels 21 of the housing 4. The roots of the teeth 26 are slightly proud of the comb back 27, the recess 36 thus formed between the roots of each pair of successive teeth accommodating a row wire 2 (in the standard rows).

The spring arm 23 previously referred to appears as a l3 tooth above the other l2.

The free end of each tooth 26 is formed with a horizontal slot 33 (shown in FIGS. 3 and 5) which is open towards the front face of the comb, i.e. that shown in FIG. 5. This slot 33 has a vertical width which is a close fit on the diameter of the row wires 2. Immediately before the slot 33 on each tooth is an upper ramp formation 34 which is an upward incline leading smoothly into the slot 33. On the underside of each tooth 26 is a lower ramp formation 35 which is downwardly inclined towards the slot 33 below. The two ramp formations 34 and 25 on adjacent teeth form a funnel for the guidance of a row wire 2 on the insertion from the root end of a tooth 26 towards the free end.

The ramp and slot formations on the end of each tooth 26 extend uniformly transverse to the comb, to the right in FIG. 3. This extension is accommodated by the offsetting of the portion 15 of the back plate of the next housing 4, as shown in FIG. 4. The recess 36 referred to above, between the roots of the teeth 26, is thus more nearly aligned with the center of the slot 33, or, in other words, the slot 33 covers a greater part of the angle of view of this recess 36 (when the recess is closed by the adjacent housing backplate 6) and can thus be less easily avoided by the leading end of a row wire on insertion into an assembly of the housings.

The teeth 26 of the comb are inclined slightly upward so that a row wire 2, located in the slots 33 of successive columns, is not obstructed by the roots of the teeth 26 but lies freely in the center of the recess 36. Each row wire 2 is thus supported within the matrix by the slots 33 of all the combs of the row. A resilient mounting is thus provided for that section of a row wire 2 subject to the deflecting force of a comb 25 in the operation of a contact set. The wire 2 is supported at one column pitch on either side of the deflection point by the tooth slots 33 of the adjacent combs of the row.

The downward biassing of each comb 25 of the two spring arms 22 and 23 ensures that the 12 row wires 2 of a contact set are returned to their normal unstressed state by the pressure of the upper walls of the associated slots 33. The row wires 2 are thus located vertically by the tooth slots 33 and horizontally by the recesses 36 and adjacent back plate 6.

The position of the column wires 3 relative to the row wires 2 can be seen from FIGS. 3 and 5. The driving point of each tooth tip (that is, the walls of the slot 33) lies between and slightly beneath the two wires constituting each column wire 3.

Referring to FIG. 3 particularly, the column wires 3 extend through every tier and every column as in the column shown. TI-Ie looped end of each wire 3 is on the right, as shown, and the left-hand ends lie freely, that is, without electrical connection, in the connector housing 14.

As mentioned previously the row wires 2 extend through the right-hand rows in the manner just described. At one end of the matrix (on the left in FIG. 1) these l0 rows each of l2 tiers of row wires 2 extend through an assembled column of further connector housings. These row connector housings are assembled in the same manner as a column of comb housings. Each row connector housing houses 12 row connectors, i.e., terminal tags 43, which protrude from the narrow face of the connector housing. The 12 row wires 2 extend through the housing and protrude from it alongside the row connectors. A wrapped connection is then made between the row wires 2 and the row connectors.

In the remaining three rows there are, of course, no continuous row wires to be connected to terminals. However each column in each of these three level-switching rows has four terminal wires 18 which are of the same diameter as the standard row wires 2 but which are only relatively short lengths and of approximately right-angle form. Each such terminal wire 18 has one arm of length approximating to the length of a tooth 26 of a comb 25 and the other arm of length sufficient to extend from the comb of the level-switching row in question, parallel to the columns, to column connectors 41 (i.e., terminal tags) mounted in the column connector housing 14 as shown in FIG. 1. The short arm of each terminal wire 18 lies on the tooth of a comb supported in the slot 33, in a position similar to that of a standard row wire 2. The longer arm of each terminal wire extends through the hole 17 in the wall 6 of the comb housing 4 and through similar holes in adjacent rows (if any) to the connector housing 14 where it is cranked as shown in FIG. 4 and supported in a slot to restrict rotational movement. Wrapped connections are made with the column connectors 41.

As shown in FIG. 3, four terminal wires 18 are positioned on the lowest four teeth in row 1, four terminal wires 18 are positioned on the middle four teeth of row 2 and four on the upper four teeth of row 3. Clearly, operation of the contact set of row 1 will give the four lowemtost column connectors 41 access to the four column wires 3 in the same tiers. Access to the middle and upper groups of column wires is similarly obtained by operation of the other two contact sets. The remaining columns are identical in respect of their terminal wire connections.

In assembling the matrix, first the 130 combs 25 and comb housings 4 are assembled. In the case of the level-switching rows the elbow shaped terminal wires 18 are also inserted at this stage and the three housings 4 for these rows are interlocked. The columns are then made up to 13 subassemblies of housings 4 and combs 25 by interlocking the comb housings as described. A connector housing 14 for each column is assembled by inserting 12 connectors 41 in recesses in the housing and then mating the connector housing 14 with the first comb housing 4, feeding the terminal wires 18 through the connector housing 14 at the same time.

After assembling the IQ columns a further column of row connector housings is assembled. The row housing and the column housings 14 are in fact identical moldings but formed so that a tenninal tag 43 or 41 may be inserted to protrude from the narrow or broad face according to the use. The terminal tags are of hook or uneven U shape to provide anchorage in the housing.

The end moldings of the l 1 column assemblies have spigots 10 and 42 which locate in upper and lower clamping strips which run along the ends of the column assemblies. Tie rods (the heads of which are shown in FIG. 1) extend through each column assembly (through the spigots 10) to clamp the whole housing matrix between the clamping strips. The lower clamping strip (55 in FIG. 1) has flanges 56 for mounting the matrix on a main plate 61 beneath which the operating mechanism is mounted.

After assembling the matrix of housing moldings the column wires 3 are inserted from one side of the assembly. The countersinking of the holes 16 and the relatively short distance between the plates 6 of the comb housings 4 facilitates the insertion of the column wires. The side plate for retaining the row wires of row 13 is then fixed and subsequently a cover plate to retain the column wires. The row wires 2 are inserted from one end of the assembly the row wires being fed initially into the recesses 36 which then guide the wires sufficiently for them to enter the slots 33. Wrapped connections are made between the row wires 2, the tenninal wires 18 and the respective terminal tags 41 and 43.

Iclaim:

1. A crossbar switch including a wire conductor matrix, said wire conductor matrix comprising a plurality of tiers of wire conductors which, in each tier are arranged as rows and columns so that corresponding row wires in the different tiers form row planes and corresponding column wires in the different tiers form column planes, the intersection of a said row plane and a said column plane providing a crosspoint contact set which comprises a contact pair in each said tier, a respective comb member bodily movable for the operation of each cross-point contact set, each said comb member having a respective cantilever tooth for each contact pair of the associated crosspoint contact set, each said tooth having a forked or apertured tip in driving engagement with the associated row wire for displacement of the said row wire into and out of contact with the column wire of the contact pair.

2. A crossbar switch according to claim 1 wherein each said row wire is located with respect to movement within a said row plane by said engagement of the row wire with the teeth of the comb members of that row plane.

3. A crossbar switch according to claim 2 wherein each said comb member is mounted in a respective comb housing which guides the movement of the comb member transverse to said tiers, spring means being incorporated between said comb member and said comb housing to bias the comb member in a direction such as to maintain an unstressed condition of the row wires engaged thereby.

4. A crossbar switch according to claim 3 wherein movement of said comb member in its housing member under or against the influence of said spring means is limited by respective stops integral with the comb and housing members, so that each comb member and its housing member forms a selfbiassed sub assembly.

5. A crossbar switch according to claim 3 wherein said spring means comprises a resilient cantilever integral with one of the comb and housing members, the tip of said cantilever bearing upon the other one of the comb and housing members.

6. A crossbar switch according to claim 3, wherein said spring means comprises an integral resilient cantilever on each of the comb and housing members, the tip of one said cantilever bearing upon the other. 

1. A crossbar switch including a wire conductor matrix, said wire conductor matrix comprising a plurality of tiers of wire conductors which, in each tier are arranged as rows and columns so that corresponding row wires in the different tiers form row planes and corresponding column wires in the different tiers form column planes, the intersection of a said row plane and a said column plane providing a crosspoint contact set which comprises a contact pair in each said tier, a respective comb member bodily movable for the operation of each cross-point contact set, each said comb member having a respective cantilever tooth for each contact pair of the associated crosspoint contact set, each said tooth having a forked or apertured tip in driving engagement with the associated row wire for displacement of the said row wire into and out of contact with the column wire of the contact pair.
 2. A crossbar switch according to claim 1 wherein each said row wire is located with respect to movement within a said row plane by said engagement of the row wire with the teeth of the comb members of that row plane.
 3. A crossbar switch according to claim 2 wherein each said comb member is mounted in a respective comb housing which guides the movement of the comb member transverse to said tiers, spring means being incorporated between said comb member and said comb housing to bias the comb member in a direction such as to maintain an unstressed condition of the row wires engaged thereby.
 4. A crossbar switch according to claim 3 wherein movement of said comb member in its housing member under or against the influence of said spring means is limited by respective stops integral with the comb and housing members, so that each comb member and its housing member forms a self-biassed sub assembly.
 5. A crossbar switch according to claim 3 wherein said spring means comprises a resilient cantilever integral with one of the comb and housing members, the tip of said cantilever bearing upon the other one of the comb and housing members.
 6. A crossbar switch according to claim 3, wherein said spring means comprises an integral resilient cantilever on each of the comb and housing members, the tip of one said cantilever bearing upon the other. 